Etching device for glass substrate

ABSTRACT

An etching device for a glass substrate is disclosed, in which an etchant is maintained at a constant amount to uniformly etch the glass substrate. The etching device for a glass substrate includes an etch container having an etchant to etch the glass substrate,. a container cover for covering the etch container, a drain at a corner portion of an upper portion of the etch container, for collecting the etchant overflowed from the etch container, and a drain tube for serving as a path of the etchant between the drain and the etch container.

[0001] This application claims benefit of Korean Patent Application No. 2000-83100, filed on Dec. 27, 2000 the entirety of which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an etching device for a glass substrate of a liquid crystal display (LCD) panel, and more particularly, to an etching device for a glass substrate in which an amount of etchant is maintained at a constant to uniformly etch the glass substrate by an exothermic reaction between the etchant and the glass substrate.

[0004] 2. Discussion of the Related Art

[0005] Recently, research of flat panel displays such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescent display (ELD), vacuum fluorescent display (VFD), etc., is being performed and these displays are being used in various apparatuses.

[0006] Among these displays, LCDs are most widely used because they have good picture quality and low power consumption characteristics. They are being used, for example, as the display in portable televisions and notebook computers.

[0007] Portable televisions or notebook computers are becoming increasingly popular due to their lightness in weight. A main component of technology development is to decrease their weight. To this end, there are specific efforts to decrease the weight of the LCD itself.

[0008] Various ways for decreasing the weight of the LCD have been tried. However, limits exist in decreasing the weight and size of the main elements of the LCD due to limitations in the previous technology and the LCD structure.

[0009] In the meantime, a glass substrate, which is one of the most basic elements of the LCD, still has margin to decrease the weight of the LCD according to developments in processing technologies. Since the glass substrate occupies most of the total weight of the LCD, research for decreasing the weight of the glass substrate is being performed for the purpose of decreasing the weight of the LCD.

[0010] In order to decrease the weight of the glass substrate, its thickness should be decreased preferentially. However, if the thickness decreases below a specific value, the glass substrate is broken during its processing or cracks are generated. Accordingly, this is one of the limitations in decreasing the thickness of the glass substrate.

[0011] One way for decreasing the thickness of the glass substrate, after an LCD panel is fabricated using a glass substrate having more than the specific thickness, a surface of the glass substrate is etched by dipping the glass substrate into an etching bath.

[0012] This method, however, has disadvantages in that the glass substrate is disproportionally etched due to the foreign particles generated during the etch process to the etched surface of the glass substrate and thus the surface of the glass substrate becomes irregular.

[0013] A related art etching device for a glass substrate will now be described with reference to the accompanying drawings.

[0014]FIG. 1 is a block diagram of a related art diagramming an etching device for glass substrates.

[0015] First, a method for fabricating an LCD using a glass substrate is described. In this method a pair of large-sized glass substrates each having plural pixel regions are prepared. An LCD panel is fabricated using the pair of glass substrates by attaching the glass substrates with a space between the glass substrates. The LCD panel is cut to have a selected size. Liquid crystal is injected into the space between the glass substrates.

[0016] Specifically, in the LCD panel, on one glass substrate, generally called “TFT substrate” comprising gate lines and data lines normal to the gate lines are formed to thereby define pixel regions in a matrix arrangement. A pixel electrode is formed on the defined unit pixel region. On the other glass substrate, generally called “color filter substrate”, a color filter of red, green, blue (R, G, B) and a common electrode are arranged. The TFT substrate and the color filter substrate are aligned with a space for the liquid crystal between them and then they are attached to each other by a sealant. The attached substrates are cut and then the liquid crystal is injected into the space.

[0017] In the aforementioned LCD panel fabrication process the attached substrates are etched to decrease the weight of the substrates, wherein this step is conducted prior to cutting the attached substrates.

[0018] Referring to FIG. 1, the related art etching device 8 includes: an etching bath 1 for etching a glass substrate using an etchant to etch the glass substrate to a desired thickness; a cleaning bath 6 for cleaning the etched substrate wherein the cleaning bath consists of deionized or distilled (DI) water; a drying bath 7 for drying the cleaned substrate; an etchant recycling part 2 for reproducing the etchant used in the etching bath 1; a DI supply part 3 for supplying the deionized or distilled water; an undiluted etchant supply part 4 for supplying an undiluted etchant; and a etchant mixing part 5 for mixing the DI and the undiluted etchant supplied from the DI supply part 3 and the undiluted etchant supply part 4 respectively with the recycled etchant supplied from the etchant recycling part 2 and supplying the mixed etchant to the etching bath 1.

[0019]FIG. 2 shows a detailed structure of the etching bath 1 described in FIG. 1. Referring to FIG. 2, the etching bath 1 includes: a container la containing the etchant; a gas supply tube 1 b for supplying nitrogen (N₂) or oxygen (O₂); and a container cover 1 d for covering the upper portion of the container 1 a.

[0020] The etchant mixing part 5 is connected to the etching bath 1 to supply the mixed etchant to the etching bath 1. The DI supply part 3 and the undiluted etchant supply part 4 are respectively connected to the etchant mixing part 5 to supply the DI water and the undiluted etchant to the etchant mixing part 5.

[0021] The etchant mixing part 5 has to mix the DI water and the undiluted etchant in a constant concentration. To do so, a concentration measuring part 5 a is provided in the etchant mixing part 5. The concentration measuring part 5 a measures the concentration of the etchant mixed in the etchant mixing part 5. When the concentration of a mixed etchant in the etchant mixing part 5 reaches a reference concentration, the concentration measuring part 5 a informs a control part (not shown) of such a fact. The control part stops the supply from the DI supply part 3 and the undiluted etchant supply part 4 to the etchant mixing part 5.

[0022] The glass substrate is etched in the container 1 a of the etching bath 1 by an exothermic reaction between the glass substrate and the mixed etchant supplied from the etchant mixing part 5.

[0023] A method for etching the glass substrate of the LCD panel using the aforementioned related art etching device will be described below.

[0024] As described above, after the etchant of a constant concentration is filled in the container 1 a, the attached glass substrates are installed in a cassette (not shown) to be placed in the container 1 a filled with the etchant, so that the glass substrate of the LCD panel is etched.

[0025] After the glass substrate installed in one cassette is etched, the etchant contained in the container 1 a is supplied to the etchant recycling part and a new etchant is supplied to the container 1 a through the etchant mixing part 5 to etch more glass substrates.

[0026] The aforementioned related art glass substrate etching device has several problems.

[0027] As described above, the etchant of a constant amount is supplied, and the glass substrate is etched while bubbles are generated by supplying a gas. Bubbles are burst into the etchant bath causing the etchant to be partially lost, thereby reducing the amount of the etchant. Accordingly, it is difficult to uniformly control the etchant.

[0028] Once the etchant is reduced, the temperature increases quickly by the exothermic reaction. In this case, it is difficult to uniformly control the etch rate of the glass substrate. The nonuniform etch rate causes a number of problems such as the generation of spots.

SUMMARY OF THE INVENTION

[0029] Accordingly, the present invention is directed to an etching device for a glass substrate that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

[0030] An object of the present invention is to provide an etching device for a glass substrate in which a drain is formed at a comer portion of an etch container to prevent an etchant from overflowing.

[0031] Another object of the present invention is to provide an etching device for a glass substrate in which an etchant is maintained at a constant amount to prevent the glass substrate from being unevenly etched and to avoid poor etching.

[0032] Additional features and advantages of the invention will be set forth in the description that follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the scheme particularly pointed out in the written description and claims hereof as well as the appended drawings.

[0033] To achieve these and other advantages in accordance with the present invention, as embodied and broadly described, an etching device for a glass substrate according to the present invention includes an etch container having an etchant, a drain at a comer portion of an upper portion of the etch container, for collecting the etchant overflowed from the etch container, and a drain tube between the drain and the etch container.

[0034] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:

[0036]FIG. 1 is a block diagram illustrating a related art etching device for a glass substrate.

[0037]FIG. 2 is a detailed sectional view illustrating a related art etching bath.

[0038]FIG. 3 is a plan view illustrating an etching bath of an etching device for a glass substrate according to the present invention.

[0039]FIG. 4 is a sectional view taken along line I-I′ of FIG. 3 in accordance with the first embodiment of the present invention.

[0040]FIG. 5 is a sectional view taken along line I-I′ of FIG. 3 in accordance with the second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

[0042] A block diagram of an etching device for a glass substrate in accordance with the present invention is configured in the same manner as a general block diagram of FIG. 1 except for an etching bath. A configuration of the etching bath will be described below with reference to FIGS. 3 to 5.

[0043] As shown in FIGS. 3 and 4, the etching bath 11 includes an etch container 11 a for containing an etchant 11 g such as Hydrofluoric acid (HF) to etch a glass substrate 10; a bubble plate 11 h at a lower portion of the etch container 11 a and having a plurality of holes wherein this bubble plates allows for uniformly distributing bubbles using a gas supplied from an outside source, a gas supply tube 11 b for supplying a gas such as nitrogen (N₂) or oxygen (O₂) to the bubble plate 11 h; a container cover 11 f for covering an upper portion of the etch container 11 a; a drain 11 e formed at a corner portion of the upper portion of the etch container 11 a, for preventing the etchant 11 g from overflowing to the outside due to the bubbles generated in the etch container 11 a, and a drain tube 11 d providing a path for the etchant 11 g between the drain 11 e and the container 11 a. The bubble plate 11 h has a plurality of holes. A plurality of glass substrates 10 are placed in the etch container 11 a loaded in a cassette 11 i.

[0044] A temperature sensor 11 c is utilized in the etch container 11 a for many purposes, such as to measure temperature variations caused by an exothermic reaction between the glass substrate 10 to be etched in the etch container 11 a and the etchant 11 g. The temperature may vary according to the number of glass substrates being etched and the required etching thickness of the glass substrates 10. The temperature sensor 11 c is also utilized by indicating an end point of the etching process.

[0045] In the aforementioned etching bath 11, a pump 21 is used for supplying the etchant from an etchant mixing part 14, a DI supply part 12, and an undiluted etchant supply part 13 to the etchant container, for example. Although not shown, an etchant recycling part, a cleaning part, and a drying part are further formed in the etching bath 11.

[0046] At this time, as shown in FIG. 4, the container cover 11 f completely covers the etch container 11 a and its comer portions are formed in the drains 11 e. The comer portions of the container cover 11 f are formed in such a manner that they are dipped into the etchant 11 g within the drain 11 e. The container cover 11 f has an outlet allowing the flow of supplied gas out. This configuration allows several glass substrates loaded on a cassette enable to be uniformly etched simultaneously.

[0047] Also, as shown in FIG. 5, the comer portion of the container cover 11 f may be formed in the drain 11 e in such a manner that it is not dipped into the etchant 11 g within the drain 11 e. It should be understood that these are not the only configurations and other configurations have been contemplated and these would be apparent to those skilled in the art.

[0048] The mechanism of the etching device for the glass substrate according to the present invention will be described as follows.

[0049] The glass substrate 10 to be etched is arranged within the etch container 11 a.

[0050] The pump 21 between the etching bath 11 and the etchant mixing part 14 is operated. Then, the etchant is supplied to the etchant container 11 a to reach a constant height within the etch container 11 a.

[0051] At this time, the etch container 11 a is connected with the drain 11 e through the drain tube 11 d, so that the height of the etchant within the etch container 11 a becomes equal to the height of the etchant within the drain 11 e.

[0052] Once the etchant is supplied to the etch container 11 a as described above, for example, the glass substrate is etched by an exothermic reaction between the glass substrate 10 and the supplied etchant. At this time, a gas is supplied to the supply tube 11 b to remove impurities generated by the reaction of the glass substrate 10. Bubbles of gas are generated from the holes of the bubble plate 11 h so that a reactant on the surface of the glass substrate 10 is removed by the bubbles. At the same time, the bubbles are burst out of at an upper surface of the etchant 11 g. Thus, the etchant flows out from the etch container 11 a, wherein the etchant is collected in the drain lie.

[0053] The etchant 11 g collected in the drain 11 e flows into the etch container 11 a through the drain tube 11 d.

[0054] Accordingly, the etchant 11 g within the etch container 11 a is maintained at a constant amount to etch the glass substrate.

[0055] At this time, the etchant serves to remove SiO₂ contained in the glass substrate, and the reaction between the glass substrate and the etchant of HF can be expressed as SiO₂+HF→SiF₄+2H₂O+E, wherein E represents a heat generated when the glass substrate is etched. The etch rate can be measured by measuring the generated heat, regardless of the concentration of the etchant and etch time.

[0056] Therefore, a temperature of a reaction heat is calculated depending on the number of the glass substrates. The etching process is stopped when the calculated reaction heat is obtained. This process enables uniformity of etch thickness across the glass substrates.

[0057] As described above, the etching device for a glass substrate according to the present invention has the following advantages.

[0058] The etchant is collected at the corner portion of the etch container to prevent the etchant within the etch container from flowing out, and the drain and the drain tube are formed to circulate the etchant within the etch container. Accordingly, the etchant can be maintained at a constant amount and level within the container.

[0059] Furthermore, since the level and volume of the etchant is maintained unchanged, the etch thickness of the glass substrate can be controlled using a temperature controller by the exothermic reaction between the glass substrate and the etchant. This allows an etching process such that the glass substrate can be etched at a uniform thickness.

[0060] The foregoing embodiments are merely exemplary and are not to be construed as limiting the present invention. The present teachings can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. 

What is claimed is:
 1. An etching device for a glass substrate comprising: an etch container having an upper portion, having a comer portion, the etch container for receiving an etchant; a drain at the comer portion, for collecting etchant overflowed from the etch container; and a drain tube between the drain and the etch container.
 2. The etching device for a glass substrate of claim 1, further comprising: a container cover over the etch container; a bubble plate established at a lower portion of the etch container; a gas supply tube for supplying gas to the bubble plate; and a temperature sensor in the etch container.
 3. The etching device for a glass substrate of claim 2, wherein the gas is selected from the group consisting of Nitrogen and Oxygen.
 4. The etching device for a glass substrate of claim 2, wherein the bubble plate includes a plurality of holes.
 5. The etching device for a glass substrate of claim 2, wherein the container cover includes a comer portion formed in the drain region.
 6. The etching device of claim 5, wherein the comer portion of the container cover is dipped into etchant within the drain.
 7. The etching device for a glass substrate of claim 5, wherein the container cover further includes an outlet for flowing the supplied gas out.
 8. The etching device for a glass substrate of claim 5, wherein the comer portion of the container cover is not dipped into etchant within the drain.
 9. The etching device for a glass substrate of claim 1, wherein the etchant includes Hydrofluoric acid (HF).
 10. An etching device for a glass substrate comprising: an etching bath including an etch container for holding an etchant, the etch container including an upper portion having a comer portion, the etch bath having a drain formed at the comer portion; a drain tube between the drain and the etch container; a DI supply part and an undiluted etchant supply part for supplying DI water and an undiluted etchant to the etching bath; an etchant recycling part for recycling the etchant; and a mixing part for mixing the DI and the undiluted etchant supplied from the DI supply part and the undiluted etchant supply part.
 11. The etching device for a glass substrate of claim 10, wherein the etchant is HF.
 12. The etching device for a glass substrate of claim 10, further comprising: a cleaning bath for cleaning the glass substrate etched in the etching bath; and a drying bath for drying the cleaned glass substrate.
 13. The etching device for a glass substrate of claim 10, wherein the etching bath further includes: a container cover over the etch container; a bubble plate at a lower portion of the etch container; a gas supply tube for supplying gas to the bubble plate; and a temperature sensor in the etch container.
 14. The etching device for a glass substrate of claim 13, wherein the gas includes one of Nitrogen and Oxygen.
 15. The etching device for a glass substrate of claim 13, wherein the bubble plate includes a plurality of holes.
 16. The etching device for a glass substrate of claim 13, wherein the container cover includes a comer portion formed in the drain.
 17. The etching device for a glass substrate of claim 16, wherein the corner portion of the container cover is dipped into etchant within the drain.
 18. The etching device for a glass substrate of claim 16, wherein the container cover further includes an outlet for flowing the supplied gas out.
 19. The etching device for a glass substrate of claim 16, wherein the comer portion of the container cover not being is dipped into etchant within the drain. 